So, here we have an example problem that says rheumatoid arthritis causes pain when joints move. Which joint type is most likely affected? And we've got these four potential answer options down below. Now, the biggest clue we have here in this problem is that it says rheumatoid arthritis causes pain when joints move. Now, when we're classifying joints based on their movement, that leads us to the functional classes of joints, which recall are the synarthroses, amphiarthroses, and diarthroses.
Which are all listed here as potential answer options. Now, recall that synarthroses are still or stationary joints that do not move. So, these are also known as immovable joints. And so, if we're thinking about joints moving, it's not going to be the synarthroses. And so for that reason, we can eliminate answer option a.
And if we can eliminate answer option a, that also means we can eliminate answer option d, which says that all 3 functional joint classes are affected. And so, now we're between option b, amphiarthroses, or option c, diarthroses. And again, when we are thinking about movement it's the diarthroses that allow for dynamic movement. And so, option c is going to be the correct answer for this example. Amphiarthroses recall only allow for a little movement.
And so, it is true that rheumatoid arthritis is an autoimmune disease that affects diarthroses, or joints that have dynamic movement. And so because that's the case, that concludes this example, and I'll see you all in our next video.
